Often when landscaping terrain, it is desirable to create a change in elevation between two distinct land areas using a steep slope or an encompassing embankment. The grade or angle of the slope or embankment rising off a horizontal plain often exceeds the natural angle of repose of the slope or embankment. This makes the slope or embankment susceptible to the erosion or sloughing off of its surface due to its own weight or erosion of its surface by water from rain or irrigation. The instability of a steep slope or embankment surface makes it difficult to maintain. Furthermore, such an unstable surface hinders the growth of stabilizing vegetation.
Typically, stabilization of a steep slope or embankment is accomplished by covering the surface with a structural facing keyed into the toe of the slope. This serves to control sloughing and/or erosion. Another approach has been to replace the slope with a structural retaining wall having a relatively vertical face. However, these types of solutions are often aesthetically displeasing and restrictive to the landscaper because they force the shape of the slope or embankment to conform to the surface shape and texture of the chosen surface protection structure and restrict the growth of vegetation (a natural slope stabilizer) over the surface of the slope or embankment.
Additionally, the above solutions (and others) may require construction skills beyond that of the amateur landscaper; they may be permanent structures requiring continuing costly maintenance; or they may be cost prohibitive due to the manufacturing or construction costs.
A number of devices attempt to resolve the problems associated with stabilizing sloped embankments. Among these are U.S. Pat. No. 4,050,254 to Meheen et al., U.S. Pat. No. 4,503,649 to Sciortino, U.S. Pat. No. 4,707,962 to Meheen, U.S. Pat. No. 5,066,353 to Bourdo, U.S. Pat. No. 5,134,815 to Pickett, U.S. Pat. No. 5,145,287 to Hooper et al., U.S. Pat. No. 5,337,527 to Wagenaar, U.S. Pat. No. 5,456,555 to Bokeler, and U.S. Pat. No. 5,536,111 to Doernemann.
U.S. Pat. No. 4,050,254 to Meheen et al. discloses a modular assembled retaining wall which is constructed by founding a plurality of precast tie-back elements in laterally spaced relationship along a grade line. This, however, necessitates considerable reshaping of the embankment because the tie-back means extend vertically back into the embankment, thus requiring either that they be driven back into the soil or that a substantial amount of soil be used to cover each horizontal tier as it is created.
U.S. Pat. No. 4,503,649 to Sciortino discloses pre-manufactured modular blocks which may interlock to form breakwaters, harbor dams and the like. The modular blocks involve a cylindrical element and a wing arranged substantially at half height of the cylindrical body. The wing is provided with an open cavity arranged to embrace the cylindric element of similar blocks. These modular blocks, however, provide no means whereby vegetation could be grown were they used for stabilizing an embankment.
U.S. Pat. No. 4,707,962 to Meheen discloses a cascade wall structure made up of generally rectangular members with end ribs and curved panels having curved ends which interlock with curved surfaces on the ribs of the members for creating a variety of wall structures for different purposes and uses. These devices, however, are relatively complex and therefore may lack utility for persons not experienced in construction.
U.S. Pat. No. 5,066,353 to Bourdo discloses a shoreline prevention bulkhead system which employs a series of interlocking fiberglass panels. Each panel has elongated male and female interlocking elements extending along the opposite side edges such that, by introducing one end of the male interlocking element of a first panel into an adjacent panel and sliding the interlocking elements together, a secure panel joint is achieved. However, these panels do not allow for any sloping of the embankment.
U.S. Pat. No. 5,134,815 to Pickett discloses a barrier structure including at least one panel disposed to extend generally along a fence line, the panel having an engaging element for pivotal joining of the panel to a member of the structure. Again, like Bourdo and Hooper, using a panel to form a barrier effectively precludes sloping of the embankment.
U.S. Pat. No. 5,145,287 to Hooper et al. discloses plastic panels and a ground erosion barrier made therefrom. The panels are configured in a stretched Z-shape cross sectional design with opposed male and female interlock edges for mating association with adjacent panel strips. As with the Bourdo device described above, this barrier does not allow for any sloping of the embankment.
U.S. Pat. No. 5,337,527 to Wagenaar discloses a building block that requires conforming the slope or embankment surface shape both vertically and horizontally to the constant vertical slope built into the system and a strict adherence to installing the system in stacked level layers. In addition, the block prohibits the growth of vegetation within the limits of the systems surface.
U.S. Pat. No. 5,456,555 to Bokeler discloses a structural set of angle elements fitting into one another. The set consists of a system of commonly shaped elements having only an incremental ability to conform to changes in the vertical grade of a slope and requires a strict adherence to the installation of the system in stacked level layers. Both of these attributes will require conforming the slope or embankment's surface shape to that of the installed system.
U.S. Pat. No. 5,536,111 to Doernemann discloses an adjustable erosion control wall including a plurality of individual panels, each panel having a tongue projecting from one end and a groove formed in the opposite end. The panels of the retaining wall are pivotally and vertically slidably connected with the tongue of one panel engaged within the groove of an adjacent panel. This device possesses the same weaknesses as those discussed immediately above.
The above reference summaries are only representative of the elements disclosed in each reference. Each reference should be read individually for what it actually teaches. The references described above are considered pertinent to the disclosure and are hereby incorporated by reference. However, in spite of the existence of these devices for stabilizing embankments, controlling erosion and other similar uses, most of these devices are either too complex or too expensive for lay people to implement, or are composed of assemblies of vertical panels, which precludes any sloping of the embankment as might be desirable in various landscaping implementations. Further, these devices are not overly versatile in that they are only usable for earthen embankment stabilization.